Brief description
The Aqua satellite platform carries a MODIS sensor that observes sunlight reflected from within the ocean surface layer at multiple wavelengths. These multi-spectral measurements are used to infer the concentration of chlorophyll-a (Chl-a), most typically due to phytoplankton, present in the water. An empirical relationship is then used to compute an estimate of the relative abundance of three phytoplankton size classes (micro, nano and picoplankton). The methods used to decompose chl_oc3 are described by Brewin et al in two papers in 2010 and 2012. The two methods, denoted Brewin2010at and Brewin2012in, used calibration data from the Atlantic and Indian Oceans respectively. Users should note that these are unvalidated experimental products and they should familiarise themselves with the underlying algorithms and methodologies described in the published literature before making use of them. The data are produced from the same data stream as the MODIS Chla_oci data set (https://catalogue-imos.aodn.org.au:443/geonetwork/srv/api/records/d7a14921-8f3f-4522-9a54-e7d1df969c8a). Data are provided as two files per day, one with the percentage of nanoplankton, and one for picoplankton. The percentage of microplankton is computed as the balance to 100%, that is %micro = 100 - %nano - %pico. This collection was removed from the AODN Portal in March 2023, please refer to the Brewin 2012 collection which supersedes this one - https://catalogue-imos.aodn.org.au:443/geonetwork/srv/api/records/bc428d0b-eff7-41b9-8d4c-10e666ee1312Lineage
Statement: The radiometric sensitivity of the MODIS sensor is evolving continuously during its mission and is monitored regularly by NASA. The SeaDAS software uses tables of calibration coefficients that are updated periodically. From time to time upgrades to the algorithms and/or the format of the calibration tables are required, in which case a new version of SeaDAS is released. These data were updated on 1 September 2020 to use processing in SeaDAS v7.5 and between 2002/07/04 and 2022/06/30 are consistent with the R2018.0 reprocessing (https://oceancolor.gsfc.nasa.gov/reprocessing/r2018/aqua/). Data between 2022/07/01-2023/01/31 and then from 2023/02/01 onwards, have been processed with two more recent releases of SeaDAS and are yet to be fully verified for consistency with NASA’s most recent processing(s). Once consistency has been established, the entire data set (from 2002/07/04) will be updated and this metadata record will be changed to reflect that. The data are produced by combining the near real time (nrt) data stream from all the available direct broadcast reception stations in Australia with delayed-mode data from NASA in the US. The data have been remapped from satellite projection into a geographic (Latitude/Longitude axes) projection (0.01 degree sampling) and are presented as a sequence of daily mosaics covering the region (80 <= Longitude <= 180, -60 <= Latitude <= +10) formatted as CF-compliant netCDF files. It should be noted that the data are not processed until the definitive spacecraft ephemeris becomes available, usually 12-24 hours after the overpass. This means that the geolocation should be of a uniformly high standard. The filenames are of the form A.P1D.Notes
CreditAustralia’s Integrated Marine Observing System (IMOS) is enabled by the National Collaborative Research Infrastructure Strategy (NCRIS). It is operated by a consortium of institutions as an unincorporated joint venture, with the University of Tasmania as Lead Agent.
CSIRO Oceans and Atmosphere
Curtin University
Created: 25 02 2015
Data time period: 07 2002
text: westlimit=80.00; southlimit=-60.00; eastlimit=179.90; northlimit=10.00
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(Satellite Remote Sensing page on IMOS website)
uri :
http://imos.org.au/srs.html
global : 8209bf83-0c3c-4fbe-9f36-41f7a5ee9913
- global : 3177b188-9d42-4ba2-ab23-3d38b217eb3a